Aligning connection for drill collars



May 25, 1943. s. SIVBECKERT 2,320,107

ALIGNING CONNECTION FOR DRILL COLLARS Filed July 14, 15941 L3 INVENTOR ASieyfi'ied sfiecker,

i BY v A TT ORNE Y Patented May 25, 1943 ALIGNING CONNECTION FOR DRILLCOLLARS Siegfried Speckert, Southgate, Calif., assignor to Abe g &Reinhold Co. Ltd., Vernon, Calif., a corporation of CaliforniaApplication July 14, 1941, Serial No. 402,364

11 Claims.

The present invention relates particularly to an aligning connectionprimarily intended for the sub-connected drill collars found to be.necessary. in modern, high speed, deep hole drilling in order to addweight to the lower or bit end of the drill string, and in this wayminimize the possibility of eccentric motion of the bit, for maintaininga straight hole and eliminating the hazard of twist-off.

In accordance with the best modern practise, drill collars are utilizedin an assembly of desired length, usually of considerable length,sometimes reaching two hundred and fifty to three hundred feet, eachcollar running as high as fifty feet in length. As those collars must becarefully manufactured of specially treated material and skilledworkmanship, they are costly and for this reason are ordinarily formedwith female threads at both ends for connection in an assembly by meansof double pin substitutes, the latter of which are commonly known assubs.

The above follows from the fact, well known in drilling practise, thatthe pins or male threaded parts of drill string connectionsconstitute'the.

weakest links of the string. Hence they are commonly eliminated fromexpensive drill collars and left to be carried by the relativelyinexpensive subs connecting the collars, so that a cracked pinnecessitates only replacement of a sub. This happens quite frequently,although theoretically at least, the pin is amply strong for the taskitperforms, as long as the drill collar assembly is such that its centerline coincides with the center line of the hole.

In practise, however, it is found that inaccuracies in the manufactureof the less carefully formed subs, results in the deflection of one ormore drill collars so that the drill collar assembly deviates from atruly straight line. This, in turn, throws severe strain upon the subpins, since the hanging drill collars tend toward a straight line. Thefrequentresult isa icracked pin or pins, and when this happens it oftenpermits alignment of the drill collar assembly and the latter thenremains effective over lengthy periods of use unless the assembly partsorthe 'joint washes out. Even if the cracked pin survives, it is obviousthat it remains at all times as a potential danger of a partedstring ora washed out connection.

out of true alignment, permit them totruly align Figure 7 is a detailside view with one another, without cracking the pin or pins of one ormore collar connecting subs.

It is therefore the primary object of the present invention toincorporate in a connection,

involving the female threads or box ends of drill .vide an aligningconnection for sub-connected drill collars by which to accomplish theelimination of the above defects in a simple, scientific manner which ismechanically correct.

'With the above in mind, the invention in its structural form at presentpreferred, is fully illustrated in the accompanying drawing, which formsa part of thi specification, and in which:

Figure 1 is a view, partly in elevation and partly in vertical section,showing the proposed connection between one end of a double pin, collarconnecting sub and an adjacent drill collar, with the yielding means ofthe present invention on the pin of the sub. p

Figure 2 is a similar view showing the yielding means within the box endof the drill collar.

. Figure 3 is a detail top plan view of the ball ring of Figure 1.

Figure 4 is a detail vertical sectional view'taken diametrically throughFigure 3.

Figure 5 is a detail side view of the ball ring of Figure 2.

Figure 6 is an elevation of a portion of a sub- .connected drill collarassembly, showing deflection of a drill collar by reason of a faulty subconnection, and l V of a double pin sub such as commonly used as a drillcollar connection.

Referring now to the above described figures of the drawing, andparticularly to Figure 7', there is shown a double pin-sub [0, the malethreads of which are on pins ll projecting endwise from its oppositeends so as to engage the female threads or boxends I2'of drill collarsI3 in the manner shown in said figure for the formation .of a drillcollar assembly capable of adding the desired weight to the lower end ofa drill string adjacent to the bit.

,Each of the collars 13, of which any number may be used in theassemblyglepending upon the desired length of the latter, and thelengths of the drill collars, is of heavy construction, and is theproduct of careful manufacture with the idea of eliminating anyirregularities, inside or out, which would create any tendency towardeccentric movement of the bit end of the drill string.

Furthermore, since the drill collars l3 are, for the foregoing reasons,in the nature of expensive equipment, they are preferably formed withfemale threads or box ends I2 at both ends thereof. In this Way the boxends l2 eliminate any weakness as to the drill collars, leaving them forconnection by double pin subs H], so that in case a pin is cracked itwill mean replacement of only a materially less expensive sub.

In practise, the subs II! are not so carefully manufactured as touniformly avoid faults, and

one of these faults is that not infrequently drill collars are deflectedout of true axial alignment, with the result that the drill collarassembly, as seen in Figure 6, will, when rotated, developeccentricityof movement and great strain will consequently be thrown upon the subpins H at the upper and lower endsof the deflected drill collar. In manyinstances this-strain results in cracking 'one or both of the pins II,and unless the assembly parts as a result of pin breakage, or aconnection washes out, the assembly will often straighten itself out dueto the relief afforded by the cracking of a pin or pins, and continue tofunction satisfactorily, although with constant danger.

To avoid the cracking of a sub pin or pins as a relief of the strain,and at the same time permit a safe relief of the strain, being theprimary object and purpose of this invention, there is shown in Figure1, by way of example, the

lower portion of one of the subs it], having its coarsely threadeddepending pin I l entering the upwardly opening, and similarly threaded,box end 12 of the next lowermost drill collar 13 of a drill collarassembly. With respect to this assembly, and more particularly eachdrill collar l3 thereof, it will be noted that the sub H] as seeninFigure 7 is-substantially less in length and therefore more rigid andunyielding.

The sub I is cutaway, as shown, at the base of its pin H, to form anannular channel or recess, one wall of which, approximately normal totheaxis of the sub, is seen provided with a cancave surface M matingwith the adjacent convex top face l5 of a ball ring l6 which sub- 5stantially interfits the annular recess or channel of the sub.

The ball ring it is formed with a lower flat face for engagement withthe end surface of the 'collar box l2 when the drill collar assembly ismade up, and its outside diameter is preferably such as to coincide withthat of the sub Ill. The inside diameter of the ball ring I6 ispreferably such as to surround the base'of the pin H of the sub 10 inslightly spaced relation thereto, creating an allowance for limitedangular shifting of the threadedly connected parts so as to relieve thepin ll of fracturing strains.

Since it is important to hold the'ball ring l6 onthe pin H in making andbreakingthe connection of drill collars and subs, going in and comingout of the hole,the inner surface of the ring preferably carries adeformable, frictional, pin gripping means, as for example, an inwardlyprotruding resilient pin gripping band IT. This band may be suitablyanchored in connection with the ring to form a part thereof, as byproviding the same of dovetailed form, seated in a'similarly shapedinner annular groove of the rin g,'the band'thus being effectiveto=prevent the ball ring from falling into the hole, without affectingthe normal function of the ball ring in use.

The above described placement of the ball ring being thus plainly setforth in its disposition around the base of the sub pin, as in Figure 1,and its general form clearly appearing in Figures 3 and 4, it remainsbut to observe that not only may this construction be utilized at bothends of the sub, but it may be used at one or both ends of the sub ifthe latter be either a double pin, pin to box, or a double box sub,since diameter than the pin carried ring l6, has its external surfaceannularly spaced from the internal surface of the box I2 and. has itslower face convex as at 20 to seat downwardly upon a mating concaveinternal surface 2| of the box, so that the ring will have a sufiicientallowance for angular shifting movement in the box to prevent fracturingstrain on the pm Hi.

Also, in the form ofFigure 2, the ring 19 will have its resilientretaining band 22 on its external surface tofrictionally engage theinternal surface of the box and thusavoid danger of displacement ofthering after it is once inserted in position. vIt is, of course, oldand well known in the art that connections between drill collars in adrill collar assembly employ taper threaded pins and boxes, and that ithas been common practise to so-form theengaging threads of suchconnections as to permit play or relative'movement between thethreadedly engaged surfaces. This has commonly been done even though itis known that where the threads are perfectly matched in the firstinstance when the drill collar assembly is'made up, the weight of thecolla'r's and bit, and the strain of initial use in a rapidlyrota'tingdrill string, quickly pulls and distorts the threads to such an extentthat the play above referred to is invariably the result. Itis,-therefore, common knowledge in the art that pl ay does exist in suchthreaded'connections'of drillcollar assemblies after actual use thereof,if not'before such use.

The present invention, it is to beunderstood, assumes the existence ofthe play above men- 'tioned'between the threadedly-engaged surfaces ofthe joints, and it will benoted that the ball joint ring proposed by thepresent invention is not only positioned so that it permits of relativeangular movement betweenthe same along its ball surface, and the pin orbox member carrying the ring, but it is also free-for permissiblelateral movement along its opposite surface with respect to the othermember. 'In other words the ball j0int ring,in orderto be effective forthe purposes of the present invention, has merely abutting contact withboth the pin and the box, and is permitted movement relative to-bothpinand box, so that its function is automatically accomplished when thecollar assembly is in .actualuse.

In practical use it is preferablethat the ball ring, either ring I6 orring I9, be formed of. hardened metal to endure repeated making andbreaking ofthe collar assembly in round trip ping, and avoid thedisadvantage of galling, and it will be understood that while I haveshown and described the invention as applied to drill collars and theirconnections, where its use is highly desirable on account of thedescribed manner in which such connections are affected in practise, itwill be appreciated that the ordinary tool joint between drill pipestands is so affected to a lesser degree, and that the invention may beapplied thereto for the same purpose, and to the same end, as that aboveoutlined.

Having thus fully described the invention, what is claimed is:

l. A drill collar assembly, comprising drill collars connected in end toend relation, and a rigid ball joint member laterally shiftable in theconnections between said collars and automatically laterally adjustableunder tension in use, for

insuring hanging axial alignment of collars connected in non-alignmentin the collar assembly.

2. A drill collar assembly, comprising drill collars, subs between andconnecting the collars in end to end relation, and a rigid ball jointmember laterally shiftably positioned in the connections between thesubs and drill collars and automatically laterally adjustable underhanging tension in use, insuring hanging alignment of the assembly andrelief of angular strain on the connec tions.

3. In an aligning connection as set forth, a taper pin, a box in whichsaid pin is threaded, said pin and box having abutment portions, and arigid ball joint member laterally shiftably interposed between saidabutment portions, and in abutting relation only with said portions,upon which the pin and box are relatively angularly shiftable to avoidfracturing strain on the pin.

4. In an aligning connection as set forth, a taper pin and a box havingengaging tool joint threads, and endwise abutment portions, and a rigidball joint member laterally shiftable between said abutment portions,and movable relative to both portions, upon which the pin is movable toa limited extent angularly relative to the box.

5. In an aligning connection as set forth, a taper pin, a box in whichsaid pin is threaded, the pin and box having opposing abutment portions,and a ball rigid joint ring interposed between said abutment portions,and laterally shiftable relative to both portions upon which the pin andbox are relatively angularly shiftable.

6. In an aligning connection as set forth, a taper pin, a box in whichsaid pin is threaded, the pin and box having abutment portions inopposition longitudinally thereof, and a rigid joint ring laterallyshiftably disposed between said abutment portions and movable withrespect to both portions, the said ring and at least one of the abutmentportions having engaging concavoconvex mating surfaces.

7. In an aligning connection as set forth, a taper pin, a box in whichsaid pin is threaded, and a hardened metal ball ring freely disposedbetween, and in relatively laterally movable cooperation with, adjacentportions of both the pin and box, permitting their limited relativeangular movements,

8. In an aligning connectionas set forth, a box, a pin threaded in saidbox and having.an annular shoulder at its base opposing the box end, andprovided with a concave abutment face, and a ring frictionally supportedon the base portion of the pin in spaced relation annularly thereof forlateral movement relative thereto, having one face abutting the box endin laterally shiftable relation, and an opposite convex face engagingthe concave face of the pin shoulder.

9. In an aligning connection as set forth, a pin, a box in which saidpin is threaded, having an internal shoulder opposing the end of the pinand presenting a concave abutment face, and a ring frictionallysupported in the box in spaced relation annularly thereof, having oneface abutting the pin end in laterally shiftable relation, and having anopposite conve face seated on the concave face of the box shoulder.

10. In an aligning connection as set forth, a pair of threadedlyconnected members consisting of a pin and a box, said members havingopposing abutment portions, and a hardened ball ring interposed betweensaid abutment portions, said ring being in laterally shiftable abuttingcontact with one of said members and supported on, and spaced annularlyfrom, the other of said members, and said latter member and theringhavin relatively engaging concave-convex faces.

11. In an aligning connection as set forth, a pair of threadedlyconnected members consisting of a pin and a box having opposing abutmentportions, a hardened metal ball ring interposed between said abutmentportions in annularly spaced relation to one of said members, saidlatter member and the ring having relatively engaging concavo-convexfaces, and a flexible, elastic band carried by said ring and protrudinglaterally therefrom into frictional engagement with the last mentionedmember to prevent displacement of said ring when the members aredisconnected.

SIEGFRIED SPECKERT.

